Have you tried something like Word to HTML - this is what I use. I'm not sure if it works with other word processors (it might), but you copy/paste your content into the WORD tab, click the HTML tab, and it tosses in the formatting tags.
Some cat asked to borrow my YT Channel to do his Super Mario Bros 3 No Game Over challenge. Why not? Here's world 1.
https://scott2.neocities.org/blog/2024-12-13-back-to-static-ultra/